1. Field of the Invention
This invention relates to a lubrication means for an internal combustion engine.
More particularly, this invention relates to a lubrication pumping apparatus actuated by one or more reciprocating piston rods in combination with a valve means internally positioned within the rod to assure that a reservoir of lubricant entrained within the rod lubricates the crankpin bearing and the wrist pin bearing of a two-cycle internal combustion engine.
2. Description of the Prior Art
Many different ways to lubricate the various rotating parts of an internal combustion engine are well-known in the art. For example, with internal combustion engines having oil reservoir sumps, lubricating holes are provided in the rod cap of a piston rod to supply lubricant to the rod crankpin bearing of the crankshaft during operation of the engine. These passages are typically drilled transverse to an axis of the crankpin. The holes are usually drilled through the rod bearing cap or a slot may be provided in the bottom of the rod cap to allow lubricant to pass into the crankpin bearing areas. This method is sufficient to lubricate the rod crankpin bearing where oil in the sump submerges the crankshaft/crankpin as the crankshaft revolves within the engine crankcase or engine block.
U.S. Pat. No. 2,280,296 teaches a means to lubricate a rod/crankpin bearing by providing a series of spiral lubricating grooves down the bearing surface of a crankshaft that terminates at the crankshaft flywheel. A port, directed from the spiral lubricating grooves through the crankpin to the interior of the bearing surfaces formed between the crankpin and the rod cap, provides a lubricating path to this bearing. The lubricant is drawn from a sump at the bottom of the crankcase, up the front of the engine to the forward end of the crankshaft, and from there, down the spiral grooves to the crankshaft to the rod bearing crankpin. There is however no means to lubricate the wrist pin connecting the rod to the piston.
A recent Office action with one of the earlier filed related patent applications has revealed the following prior art, most of which illustrates a longitudinal bore in a piston rod. The earliest, U.S. Pat. No. 634,529, illustrates an internal combustion engine which directs the source of lubricant from a crankcase sump past the crankpin bearing toward the top of the rod, terminating at a ball socket connection to a piston.
This patent does not direct a source of lubricant from the crankpin to the wrist pin.
U.S. Pat. No. 1,293,342 illustrates a scoop attached to the side of a piston rod that traps lubricant injected into the cylinder walls of an internal combustion engine, the lubricant being directed toward the crankpin end of the rod. This patent does not anticipate the present invention in that there is no internal bore in the rod.
U.S. Pat. No. 1,907,805 illustrates a hollow rod between a crankpin and a wrist pin. The lubricant is sequentially directed through an internal, hollow crankshaft into a hollow wrist pin and, from there, intermittently injected into a hollow rod to provide lubricant from the crankpin to the wrist pin. This system does not provide a column of liquid within the hollow cavity of the rod that is forced into the crankpin or the wrist pin of the engine during engine operation.
U.S. Pat. No. 2,056,901 illustrates, again, a rod with a hollow interior. A system of checkvalves alternately admit fluid to the interior of the rod as the rod reciprocates within the engine. This patent does not anticipate applicant's invention in that the fluid pick-up system and valving system is entirely different as will become clear as this application enters into the description phase.
U.S. Pat. No. 2,396,500 illustrates a hollow rod, the interior chamber being directed from a crankpin to a piston; the idea being a means to cool the piston by directing oil from the crankcase of the engine up to the piston. This patent provides a means to cool a piston and does not indicate any means to lubricate a wrist pin at the top of the rod. In fact, there is no wrist pin illustrated in this patent.
U.S. Pat. No. 2,449,657 illustrates, again, a hollow rod between a crankpin and a wrist pin. As the rod rotates within a crankcase, an opening adjacent the crankpin area picks up lubricant and ejects it adjacent cylinder walls as the piston reaches top dead center to provide a stream of lubricant on the cylinder walls as the piston reciprocates within its cylinder. This patent does not anticipate applicant's invention.
U.S. Pat. No. 2,745,390 describes a two-cycle internal combustion engine that routes a source of lubricant through the center of a crankshaft into a crankpin area and, from there, up a hollow rod between the crankpin and the wrist pin. This patent does not pick up lubricant from within a crankcase chamber directed into the hollow interior of the rod past a valving system as will be described further on in this application. This patent does not anticipate applicant's invention.
U.S. Pat. No. 2,983,334 describes a two-cycle engine which directs lubricant through a crankshaft, into a crankpin area and, from there, through a hollow rod to a wrist pin. This patent does not anticipate applicant's invention in that there is no means to pick up lubricant through the rod itself into the longitudinal bore within the rod nor is there a means to control the volume within the rod through a valve means acting in concert with a passage between a crankcase chamber and the longitudinal bore within the rod.
U.S. Pat. No. 3,396,819 describes a means to primarily lubricate the "big end" bearings, namely, the crankpin bearing of a rod/piston combination. A complicated system of cam and follower between relatively oscillating parts relieves the bearing load on the rod to allow entry of lubricant to this large bearing. This patent does not anticipate applicant's invention in that it does not direct a means to lubricate a wrist pin as well as the main bearing during operation of the engine.
U.S. Pat. No. 3,656,582 describes a method to lubricate "small end" bearings of a two-cycle internal combustion engine without depending on the angular swinging movement of the connecting rod.
Obviously, the present invention utilizes the swinging motion of the rod to both direct fluid through a passage to the internal bore in the rod while utilizing a valving mechanism to close the opening during part of the swing and open the opening during another part of the swing. This action both admits lubricant within the internal passage within the rod and prevents a column of liquid within the rod from escaping during another part of the swing or rotation of the rod. This patent does not anticipate applicant's invention.
The present invention goes beyond the state of the art in that a lubricant pumping means is provided by utilizing the reciprocating and circular motion of the piston rod to collect and drive lubricant entrained in a fuel/oil mixture within the crankcase of a two-cycle engine to the crankpin and wrist pin bearings. When the piston moves up its cylinder wall, a partial vacuum is created within the crankcase which draws a mixture of fuel and lubricant into the crankcase chamber. The rod connected between the crankpin of the engine crankshaft and the wrist pin of the piston forms an internal passage that communicates between the crankpin rod bearing and the wrist pin rod bearing. A fuel/oil rod inlet slot is positioned between the crankpin and the wrist pin. The inlet slot is oriented parallel to the shank of the rod. The slot intersects the bore in the rod and communicates between the interior of the crankcase chamber and the interior passage in the rod. Fuel and oil is "scooped" into the interior of the rod as the rod revolves around the crankshaft flywheel. When the rod rotates clockwise from about the three o'clock position to about the nine o'clock position, fuel is scooped into the inlet slot to the rod interior. A cylindrical valve body, having a flange at one end, sized to about one-third the interior dimension of the longitudinal bore in the rod, extends from the wrist pin area down to just past the slot opening to the longitudinal bore. The flange end of the cylindrical rod valve loosely nests within a shoulder formed adjacent the wrist pin area, the shoulder being wider than the flange of the cylindrical valve body. The valve body then is free to move from side to side, being "hinged" within the oversized shoulder formed near the wrist pin in the rod. As mentioned before, as the rod rotates from about the three o'clock position to about the nine o'clock position, the bottom end of the cylindrical rod valve swings away from the slotted opening in the rod body, thus allowing fuel and oil to be scooped into the longitudinal bore. As the rod swings from about the nine o'clock position to about the three o'clock position however the bottom end of the cylindrical valve body swings toward the slotted opening, closing off the slotted opening to prevent fuel and oil, entrained within the longitudinal bore in the rod, from exiting the fuel inlet slot. Thus, the cylindrical valve body moves from one side of the longitudinal bore to the other to allow fuel to enter the bore from about the three o'clock to the nine o'clock position and preventing fuel from exiting the inlet slot from about the nine o'clock position to the three o'clock position, thus assuring a full supply of fuel and oil within the chamber formed by the longitudinally extending bore in the rod. The cylindrical valve body has an internal passage or bore to allow lubricant to pass through the interior of the cylindrical valve body to enhance lubrication of the wrist pin during operation of the engine.
None of the foregoing prior art patents lubricate and cool wrist pin and crankpin bearings at opposite ends of a rod in the manner as just described relative to the present invention.